A white pettle flower in virtical. The primary purpose of a flower is reproduction. Since the flowers are the reproductive organs of plant, they mediate the joining of the sperm, contained within pollen, to the ovules — contained in the ovary. Pollination is the movement of pollen from the anthers to the stigma. Why do plants have a flower? Pollen is a collection of male reproductive cells that will fertilize ovules to produce seeds. When the flower blooms, male pollen cells are scattered by insects or by the wind. ... Some kinds of plants produce only complete flowers. Other plants produce both male and female incomplete flowers on the same plant.